1. Field of Invention
This invention is concerned with apparatus for producing inphase (I) and quadrature (Q) components of a modulated baseband input signal, and more particularly, with such apparatus utilizing digital techniques.
2. Description of the Prior Art
In many radar, sonar, and communication systems, product detectors are used to demodulate a radio frequency (RF) or an intermediate frequency (IF) signal into its inphase and quadrature components at baseband. These I and Q components, as they are commonly called, are then sampled for subsequent processing. Conventionally, the demodulation and sampling are performed using two mixers (90.degree. out of phase relative to one another), appropriate low pass filters, and analog-to-digital converters. If, however, the characteristics of the components in the two branches or channels (I and Q) are not precisely matched, distortions will result. The distortions may severely affect the performance of the overall system.